The World Health Organisation (WHO) has for the first time recommended limits on children's daily consumption of sodium which it hoped would help in the global fight against diet-related diseases becoming chronic among all populations.

In advice to its 194 member states the UN agency noted high sodium levels were a factor behind elevated blood pressure, which increases the risk of heart disease and stroke, the number one cause of death and disability worldwide.

Heart disease, stroke and other non-communicable diseases (NCDs) such as diabetes, cancer and chronic respiratory disease kill more people globally each year than all other causes combined, the agency said.

"Diet-related NCDs are chronic, and take years and decades to manifest; thus, delaying the onset of these diseases could improve lives and result in substantial cost savings," it said. "Thus, addressing, during childhood, the problem of elevated blood pressure and other risk factors for NCDs that could manifest later in life is crucial to combat NCDs," it said.

The guidelines vary depending on the child's size, age and energy needs, and apply to children over the age of two.

The WHO also somewhat revised its recommendations for adults, down to less than 2,000 mg of sodium intake per day, from the current 2000 mg, in addition to a recommendation of at least 3510 mg of potassium a day.

"Currently, most people consume too much sodium and not enough potassium," the WHO said. Potassium-rich foods include beans and peas, nuts, vegetables such as spinach and cabbage, and fruits such as bananas, papayas and dates.

Sodium is found naturally in many foods such as milk products and eggs but is present in much higher levels in processed foods, the WHO said. One 100-gram serving of bacon, pretzels or popcorn has nearly as much sodium as the daily recommended maximum, for example, at about 1500 mg.

Sticking to the WHO's recommendations would mean people would consume roughly equal amounts of potassium and sodium every day, whereas most people consume twice as much sodium as potassium, the WHO said.

"The successful implementation of these recommendations would have an important public health impact through reductions in morbidity and mortality, improvement in the quality of life for millions of people, and substantial reductions in health-care costs," the agency said.

It would be updating soon WHO guidelines on the consumption of fats and sugars, also linked to obesity and disease.